Development and Validation of a Nomogram for Predicting Pathological Upgrading in Men With Biopsy Gleason 3 + 3...

Pathological upgrading after surgery is common among men with biopsy Gleason score (GS) 3 + 3 prostate cancer who undergo radical prostatectomy and may impact prognosis, highlighting the need for preoperative risk identification. This study aimed to develop and internally validate a predictive nomogram for pathological upgrading in this surgically treated population.

Patients aged ≥ 18 years with biopsy GS 3 + 3 prostate adenocarcinoma who underwent radical prostatectomy between 2004 and 2015 were identified from the Surveillance, Epidemiology, and End Results (SEER) database. A total of 14,484 patients were included and randomly divided into a training cohort and a validation cohort in a 7:3 ratio. Multivariable logistic regression was used to construct a prediction model based on preoperative clinical variables. Model performance was assessed using discrimination, calibration, and decision curve analysis. Internal validation was performed using bootstrap resampling and 10-fold cross-validation. Survival differences between risk groups defined by the nomogram were evaluated using Kaplan-Meier analysis.

Overall, 47.9% of patients experienced pathological upgrading to a radical prostatectomy GS of 3 + 4 or higher. Age, prostate-specific antigen (PSA) level, number of positive biopsy cores, and clinical T stage were independently associated with upgrading and were incorporated into the final nomogram. The model demonstrated moderate discrimination, with an area under the curve (AUC) of 0.663 (95% CI, 0.652-0.673) in the training cohort and 0.648 (95% CI, 0.632-0.664) in the validation cohort. Bootstrap internal validation yielded an optimism-corrected C-statistic of 0.662. Calibration was satisfactory, and Brier scores were 0.228 in the training cohort and 0.231 in the validation cohort. In exploratory, unadjusted analyses, patients classified as high risk by the nomogram had significantly lower overall survival than those in the low-risk group.

The nomogram demonstrated moderate predictive performance for pathological upgrading in men with biopsy GS 3 + 3 prostate cancer who were selected for radical prostatectomy, and may assist in individualized preoperative decision-making within this surgical population.